:root {
  --picker-columns: 6;
  --bg: #f3f4f6;
  --surface: #ffffff;
  --surface-2: #e8ebf0;
  --text: #1c1f24;
  --muted: #5b6370;
  --border: #cfd5de;
  --accent: #2f6fde;
  --accent-text: #ffffff;
  --focus: #2f6fde;
  --shadow: 0 1px 3px rgb(0 0 0 / 0.12), 0 8px 24px rgb(0 0 0 / 0.08);

  --sq-light: #f0d9b5;
  --sq-dark: #b58863;
  --fog: rgb(62 72 88 / 0.72);
  --fog-hover: rgb(62 72 88 / 0.56);
  --ring: #f5c542;
  --mark-mode: #ff5a5f;
  --exact: #1f9a46;
  --amber: #f0a020;
  --lost: #d42a2a;
  --win: rgb(46 170 80 / 0.55);
  --wrong: #c00000;

  --n1: #1546c9;
  --n2: #17702a;
  --n3: #c21f1f;
  --n4: #1a237e;
  --n5: #7b1515;
  --n6: #006b5f;
  --n7: #111111;
  --n8: #4a4a4a;
  --n9: #6a1b9a;

  --label: 18px;
  --pad-top: 8px;
  --top-row: 44px;
  --status-row: 36px;
  --gap: 8px;
  --pad-bottom: 8px;
  --chrome-y: calc(var(--pad-top) + var(--top-row) + var(--gap) + var(--status-row) + var(--gap) + var(--label) + var(--pad-bottom));
  --board: min(100vw - 32px - var(--label), 100vh - var(--chrome-y), 560px);
  --board: min(100vw - 32px - var(--label), 100dvh - var(--chrome-y), 560px);
  --sq: calc(var(--board) / 8);

  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14171c;
    --surface: #1e232b;
    --surface-2: #272d37;
    --text: #e7eaef;
    --muted: #9aa3b0;
    --border: #363e4a;
    --accent: #5b8ff0;
    --accent-text: #0d1117;
    --focus: #7aa7ff;
    --shadow: 0 1px 3px rgb(0 0 0 / 0.5), 0 8px 24px rgb(0 0 0 / 0.4);
    color-scheme: dark;
  }
}

[hidden] {
  display: none !important;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  min-height: 100dvh;
  background: var(--bg);
  color: var(--text);
  line-height: 1.45;
  touch-action: manipulation;
  overflow-x: hidden;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.app {
  box-sizing: content-box;
  max-width: 600px;
  margin: 0 auto;
  padding: var(--pad-top) 16px 24px;
  display: flex;
  flex-direction: column;
  gap: var(--gap);
}

.top-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  height: var(--top-row);
  min-width: 0;
}

.top-row h1 {
  margin: 0;
  font-size: 1.25rem;
  line-height: 1.2;
  letter-spacing: -0.01em;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  min-width: 0;
}

.top-row .btn {
  flex: none;
  min-height: 40px;
  max-height: var(--top-row);
}

.end-actions {
  flex: none;
  display: flex;
  align-items: center;
  gap: 8px;
}

.end-actions[hidden] {
  display: none;
}

.banner {
  flex: none;
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 0 12px;
  border-radius: 10px;
  font-size: 0.875rem;
  font-weight: 700;
  white-space: nowrap;
  text-decoration: none;
  color: var(--accent-text);
  background: var(--accent);
}

.banner.is-lost {
  background: var(--lost);
  color: #ffffff;
}

.banner.is-won {
  background: #1f9a46;
  color: #ffffff;
}

.banner:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

.controls {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.segmented {
  display: flex;
  margin: 0;
  padding: 3px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--surface-2);
  min-width: 0;
}

.segmented label {
  flex: 1 1 0;
  position: relative;
  min-width: 0;
}

.segmented input {
  position: absolute;
  opacity: 0;
  inset: 0;
  margin: 0;
  pointer-events: none;
}

.segmented span {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 40px;
  padding: 0 6px;
  border-radius: 7px;
  font-size: 0.875rem;
  font-weight: 600;
  text-align: center;
  color: var(--muted);
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
}

.segmented input:checked + span {
  background: var(--surface);
  color: var(--text);
  box-shadow: 0 1px 2px rgb(0 0 0 / 0.18);
}

.segmented input:focus-visible + span {
  outline: 2px solid var(--focus);
  outline-offset: 1px;
}

.btn {
  appearance: none;
  -webkit-appearance: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  min-height: 44px;
  padding: 0 16px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--surface);
  color: var(--text);
  font: inherit;
  font-size: 0.9375rem;
  font-weight: 600;
  cursor: pointer;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}

.btn:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

.btn-primary,
.btn-toggle[aria-pressed="true"] {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-text);
}

.btn-toggle[aria-pressed="true"] {
  box-shadow: inset 0 0 0 2px rgb(0 0 0 / 0.15);
}

.status {
  display: flex;
  flex-wrap: nowrap;
  align-items: center;
  gap: 12px;
  height: var(--status-row);
  box-sizing: border-box;
  overflow: hidden;
  padding: 0 12px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--surface);
  font-size: 0.9375rem;
  font-variant-numeric: tabular-nums;
}

.stat {
  white-space: nowrap;
  font-weight: 600;
}

.status-text {
  margin-left: auto;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  color: var(--muted);
}

.board-wrap {
  display: flex;
  justify-content: center;
}

.board-frame {
  display: grid;
  grid-template-columns: var(--label) var(--board);
  grid-template-rows: var(--board) var(--label);
}

.ranks,
.files {
  display: grid;
  color: var(--muted);
  font-size: 0.75rem;
  font-weight: 600;
  user-select: none;
  -webkit-user-select: none;
}

.ranks {
  grid-template-rows: repeat(8, 1fr);
  align-items: center;
  justify-items: start;
}

.files {
  grid-template-columns: repeat(8, 1fr);
  justify-items: center;
  align-items: end;
}

.board {
  display: grid;
  grid-template-rows: repeat(8, 1fr);
  width: var(--board);
  height: var(--board);
  border-radius: 4px;
  overflow: hidden;
  box-shadow: var(--shadow);
  outline: 3px solid transparent;
  outline-offset: 2px;
  transition: outline-color 0.15s;
}

.board-wrap.marking .board {
  outline-color: var(--mark-mode);
}

.row {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
}

.cell {
  appearance: none;
  -webkit-appearance: none;
  position: relative;
  display: grid;
  place-items: center;
  width: 100%;
  height: 100%;
  min-width: 0;
  margin: 0;
  padding: 0;
  border: 0;
  border-radius: 0;
  background-color: var(--sq-light);
  background-image: none;
  color: var(--text);
  font: inherit;
  font-size: calc(var(--sq) * 0.6);
  font-weight: 800;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.04em;
  overflow: hidden;
  cursor: pointer;
  touch-action: manipulation;
  user-select: none;
  -webkit-user-select: none;
  -webkit-touch-callout: none;
  -webkit-tap-highlight-color: transparent;
}

.cell.shade-dark {
  background-color: var(--sq-dark);
}

.cell.fog {
  background-image: linear-gradient(var(--fog), var(--fog));
}

.cell.open {
  cursor: default;
  text-shadow: 0 0 2px rgb(255 255 255 / 0.45);
}

.cell[aria-disabled="true"] {
  cursor: default;
}

.cell.known {
  cursor: not-allowed;
  box-shadow: inset 0 0 0 max(2px, calc(var(--sq) * 0.06)) var(--ring);
}

.cell:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: -3px;
  z-index: 1;
}

.cell.mark::before {
  content: attr(data-glyph);
  opacity: 0.55;
}

.cell.mark::after {
  content: "";
  position: absolute;
  inset: max(2px, calc(var(--sq) * 0.06));
  border: 2px dashed rgb(255 255 255 / 0.85);
  border-radius: 3px;
  pointer-events: none;
}

.cell.picking {
  box-shadow: inset 0 0 0 3px var(--focus);
}

.n1 { color: var(--n1); }
.n2 { color: var(--n2); }
.n3 { color: var(--n3); }
.n4 { color: var(--n4); }
.n5 { color: var(--n5); }
.n6 { color: var(--n6); }
.n7 { color: var(--n7); }
.n8 { color: var(--n8); }

.n9 {
  color: var(--n9);
  font-size: calc(var(--sq) * 0.5);
}

.cell.pw,
.cell.pb,
.pick {
  font-weight: 400;
  font-family: "Segoe UI Symbol", "Apple Symbols", "DejaVu Sans", "Noto Sans Symbols 2", "Noto Sans Symbols", system-ui, sans-serif;
  letter-spacing: 0;
}

.cell.pw,
.pick.pw {
  color: #f8f8f8;
  text-shadow: -1px -1px 0 #1b1b1b, 1px -1px 0 #1b1b1b, -1px 1px 0 #1b1b1b, 1px 1px 0 #1b1b1b, 0 0 2px #1b1b1b;
}

.cell.pb,
.pick.pb {
  color: #1b1b1b;
  text-shadow: -1px -1px 0 rgb(255 255 255 / 0.75), 1px -1px 0 rgb(255 255 255 / 0.75), -1px 1px 0 rgb(255 255 255 / 0.75), 1px 1px 0 rgb(255 255 255 / 0.75);
}

.cell.lost {
  background-color: var(--lost);
  background-image: none;
}

.cell.win {
  background-image: linear-gradient(var(--win), var(--win));
}

.cell.mark-exact {
  box-shadow: inset 0 0 0 max(2px, calc(var(--sq) * 0.06)) var(--exact);
}

.cell.mark-piece {
  box-shadow: inset 0 0 0 max(2px, calc(var(--sq) * 0.06)) var(--amber);
}

.cell.mark-exact::after,
.cell.mark-piece::after,
.cell.mark-empty::after {
  position: absolute;
  pointer-events: none;
  line-height: 1;
}

.cell.mark-exact::after {
  content: "✓";
  top: 3px;
  right: 4px;
  font-family: system-ui, sans-serif;
  font-size: calc(var(--sq) * 0.3);
  font-weight: 800;
  color: #ffffff;
  background: var(--exact);
  border-radius: 50%;
  padding: 1px 2px;
  text-shadow: none;
}

.cell.mark-piece::after {
  content: attr(data-guess);
  top: 2px;
  right: 3px;
  font-size: calc(var(--sq) * 0.3);
  opacity: 0.8;
  text-decoration: line-through;
  text-decoration-color: var(--amber);
}

.cell.mark-empty::after {
  content: "✗";
  inset: 0;
  display: grid;
  place-items: center;
  font-family: system-ui, sans-serif;
  font-size: calc(var(--sq) * 0.75);
  font-weight: 700;
  color: var(--wrong);
  opacity: 0.85;
  text-shadow: none;
}

.picker {
  position: fixed;
  z-index: 10;
  display: grid;
  gap: 6px;
  padding: 8px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.picker-grid {
  display: grid;
  grid-template-columns: repeat(var(--picker-columns), 40px);
  grid-auto-rows: 40px;
  gap: 4px;
}

.pick {
  appearance: none;
  -webkit-appearance: none;
  display: grid;
  place-items: center;
  margin: 0;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--sq-light);
  font-size: 28px;
  line-height: 1;
  cursor: pointer;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}

.pick.is-last {
  border-color: var(--accent);
  box-shadow: 0 0 0 2px var(--accent);
}

.pick[aria-pressed="true"] {
  background: var(--sq-dark);
}

.pick:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 1px;
}

.picker-clear {
  min-height: 36px;
  font-size: 0.875rem;
}

.picker-clear:disabled {
  opacity: 0.45;
  cursor: default;
}

.result-marks {
  font-weight: 600;
}

@media (hover: hover) {
  .cell.fog:not(.known):hover {
    background-image: linear-gradient(var(--fog-hover), var(--fog-hover));
  }

  .btn:hover {
    filter: brightness(1.06);
  }
}

.result {
  padding: 16px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--surface);
  color: var(--text);
  scroll-margin-top: 8px;
}

.result p {
  margin: 0 0 8px;
}

.result h2 {
  margin: 4px 0 6px;
  font-size: 1.25rem;
  line-height: 1.25;
}

.result-headline {
  font-size: 1.125rem;
  font-weight: 800;
}

.result.is-lost .result-headline {
  color: var(--lost);
}

.result.is-won .result-headline {
  color: #1f9a46;
}

.muted {
  color: var(--muted);
  font-size: 0.9375rem;
}

.result a {
  color: var(--accent);
  font-weight: 600;
}

.result .btn {
  width: 100%;
  margin-top: 6px;
}

@media (min-width: 480px) {
  .top-row h1 {
    font-size: 1.5rem;
  }
}

@media (max-width: 479px) {
  .top-row.is-finished h1 {
    display: none;
  }

  .top-row.is-finished .end-actions {
    flex: 1;
    justify-content: space-between;
  }
}

.about {
  margin-top: 8px;
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--surface);
  color: var(--muted);
  font-size: 0.8125rem;
  line-height: 1.5;
}

.about p {
  margin: 0 0 8px;
}

.about p:last-child {
  margin-bottom: 0;
}

.about a {
  color: var(--accent);
}